P1122, P0446,P0606,P0172

Normally "too rich" is due to leaking injectors or a failed front "wide band" or "AFR" O2 sensor. Can also be low compression, bad plug or coil > weak or no spark, but you would expect a misfire DTC, which you do not have.

BTW, there is no "bank 2", only Bank 1, front and rear O2s (front controls AFR, rear confirms that the cat is there and working).

The CCV takes some power to operate, so corrosion can cause that code.

 

DTC P0606 means that the engine ECU has a CPU malfunction. The other DTC logged by that ECU are suspect until you have resolved that first issue. Resolution requires replacement of the engine ECU.

 

I do not see any corrosion or damaged pins in those at all.

 

Oh, WAY worse than "suspect", more like JUNK.

 

Regarding P1122, you can measure resistance across the various pins of the wiring harness connector for the valve. Pins 1 and 2 should be around 40 ohms. Those pins are for the motor within that valve. Then the resistance across pins 5 and 6 should be 5,700 ohms which is both sides of the variable resistor which shows valve position. Pin 4 is attached to the arm of the resistor so the resistance to pins 5 and 6 will vary depending upon the valve position.

 

Your conversation sounds like the topic I am needing to investigate on my 2006 Prius. Over the past 6 months I've had intermittent and now constant Check Engine warning lights. The code is P1121 (Coolant Flow control valve did not show a change in output voltage or the voltage changed slowly when commanded by the ELM to open or close, or following coolant recovery. Coolant Flow Control Valve Position Sensor Circuit stuck.) With this code, do you recommend replacing the connector pictured above? If yes, it it hard to replace?

 

Usually the valve would have to be replaced as it tends to stick in one position which causes the DTC to be logged.

 

Is there a video or instructions on how to find the valve and replace it? If I want to buy one - what is it called?

 

After you do the resistance checks, another test would be to apply 12V to terminals 1 and 2 and verify that the motor will move the valve from one position to the other. Also measure resistance from terminal 4 (which is the wiper arm of the variable resistor) to terminals 5 and 6 (which are the two ends of the variable resistor) and see if that measurement varies smoothly as the motor is moving.

There are several strings about the engine coolant valve and how to replace it.

I believe this is the correct valve but will leave it to you to verify the part number.

Toyota Prius Valve assembly, water with bracket. Engine - 1667021010 | Roseville Toyota, Roseville CA

 

That is the correct part number as of this past July. I've purchased 2 of the 3-ways with a ~2.5 year spread and the part number was same for both.

 

Good deal on the SLLC too.

Must know somebody at the parts counter.

 

Paul, try a quick MAF/TB cleaning for the rich code. Our '07 (~195k miles) throws it about every year or 18 months and this has been my "fix" several times over now. I've done a Techstream test-drive follow-up and watched fuel trims return to normal. Ymmv but it's been a quick and dirty for me. I use the CRC maf and throttle body/air-intake sprays, fwiw.

 

Thank you very much for your help!!